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| United States Patent |
6,000,937
|
|
Schilling
, et al.
|
December 14, 1999
|
Device for distributing and/or feeding a hot flour-like material
Abstract
A cement plant for the production of cement clinker from cement raw meal
has a flat plate shaped control element for distributing and/or
transporting-feeding a stream of hot flour-like material which is
subjected to severe thermochemical and abrasive ware. the service life of
the control element is greatly increased by constructing it as a hollow
body (19, 22) through which coolant flows from at least one inlet opening
to at least one discharge opening.
| Inventors:
|
Schilling; Horst (Cologne, DE);
Muller; Hans Gunter (Cologne, DE)
|
| Assignee:
|
KHD Humboldt Wedag AG (Cologne, DE)
|
| Appl. No.:
|
075611 |
| Filed:
|
May 11, 1998 |
Foreign Application Priority Data
| May 17, 1997[DE] | 197 20 951 |
| Jul 30, 1997[DE] | 197 32 778 |
| Current U.S. Class: |
432/106 |
| Intern'l Class: |
F27B 007/02 |
| Field of Search: |
432/14,16,58,106,77,78
|
References Cited
U.S. Patent Documents
| 4388067 | Jun., 1983 | Christiansen | 432/106.
|
| 4570549 | Feb., 1986 | Trozzi | 110/106.
|
| 4817442 | Apr., 1989 | Loosemore | 73/863.
|
| 5349910 | Sep., 1994 | Hundebol | 432/106.
|
| Foreign Patent Documents |
| 0222 044 | May., 1987 | EP.
| |
Primary Examiner: Paschall; Mark
Assistant Examiner: Wilson; Gregory A.
Attorney, Agent or Firm: Nexsen Pruet Jacobs & Pollard, LLP, Schwab, Esq.; Charles L.
Claims
What is claimed is:
1. In a cement plant for producing cement clinker from cement raw meal by
preheating the raw meal in a heat-exchanger system receiving heated gases
from a rotary kiln off-gas line and from a clinker cooler off gas line,
each of said off-gas lines having a point of entry for raw meal, and
burning the preheated raw meal to cement clinker in the rotary kiln, said
heat exchanger system comprising:
apparatus for apportioning the flow of raw meal including
a housing (21) in the shape of a breeches pipe having a raw material inlet
opening (20) at its top and two raw material discharges (23, 24) at its
bottom,
a hollow flap (22) in said housing and
a shaft (31) pivotally supporting said flap in said housing (21), said
hollow flap (22) including at least one coolant inlet opening and at least
one coolant outlet opening whereby coolant is permitted to flow through
said hollow flap (22) and said hollow flap (22) being pivotable to
selectively apportion flow of said raw material entering said inlet
opening (20) to said material discharges (23, 24) and
a hollow impingement gate (19) integrated in one of said off-gas lines
below said point of entry for raw meal in said one off-gas line, whereby
said raw meal delivered to said one off gas line is distributed by
impingement with said hollow gate (19), said hollow impingement gate (19)
having a coolant inlet opening (41), at least one coolant discharge
opening (42,43), and at least one web (39, 40) within said hollow gate
(19) for distributing coolant flow through said hollow gate (19).
2. The cement plant of claim 1 wherein said shaft (31) is hollow and said
shaft (31) presents said coolant inlet opening and said coolant discharge
opening.
3. The cement plant of claim 1 wherein said hollow flap (22) is plate
shaped and includes a web (30) transverse to the plane of said hollow flap
(22) operating to divert coolant flowing through said hollow flap (22).
4. The cement plant of claim 1, wherein said cement plant includes an
oscillating feeder for raw meal and said hollow flap (22) is a weighted
oscillating flap of said oscillating feeder for cement raw meal.
5. The cement plant of claim 1 wherein said one web (39, 40) is disposed
transverse to the plane of said gate (19) and diverts the coolant admitted
via said coolant inlet opening (41) in route to at least one coolant
discharge opening (42, 43).
6. The cement plant of claim 5 wherein at least one of said coolant
discharge openings (42, 43) and said coolant inlet opening (41) are
located in an end face of said gate (19).
7. In a cement plant for producing cement clinker from cement raw meal by
preheating the raw meal in a heat-exchanger system receiving heated gases
from a rotary kiln off-gas line and from a clinker cooler off gas line,
each of said off-gas lines having a point of entry for raw meal, and
burning the preheated raw meal to cement clinker in the rotary kiln, said
heat exchanger system comprising:
apparatus for apportioning the flow of raw meal including
a housing (21) in the shape of a breeches pipe having a raw material inlet
opening (20) at its top and two raw material discharges (23, 24) at its
bottom,
a hollow flap (22) in said housing and
a shaft (31) pivotally supporting said flap in said housing (21), said
hollow flap (22) including at least one coolant inlet opening and at least
one coolant outlet opening whereby coolant is permitted to flow through
said hollow flap (22) and said hollow flap (22) being pivotable to
selectively apportion flow of said raw material entering said inlet
opening (20) to said material discharges (23, 24).
8. The cement plant of claim 7 wherein said shaft (31) is hollow and said
shaft (31) presents said coolant inlet opening and said coolant discharge
opening.
9. The cement plant of claim 8 wherein said hollow flap (22) is plate
shaped and includes a web (30) transverse to the plane of said hollow flap
(22) operating to divert coolant flowing through said hollow flap (22).
10. The cement plant of claim 7 wherein said cement plant includes an
oscillating feeder for cement raw meal and said hollow flap (22) is a
weighted oscillating flap of said oscillating feeder.
11. In a cement plant for producing cement clinker from cement raw meal by
preheating the raw meal in a heat-exchanger system receiving heated gases
from a rotary kiln off-gas line and from a clinker cooler off gas line,
each of said off gas lines having a point of entry for raw meal, and
burning the preheated raw meal to cement clinker in the rotary kiln, said
heat exchanger system comprising:
a hollow impingement gate (19) integrated in one of said off-gas lines
below said point of entry for raw meal in said one off-gas line, whereby
said raw meal delivered to said one off gas line is distributed by
impingement with said hollow gate (19), said hollow impingement gate (19)
having a coolant inlet opening (41), at least one coolant discharge
opening (42,43), and at least one web (39, 40) within said hollow gate
(19) for distributing coolant flow through said hollow gate (19).
12. The cement plant of claim 11 wherein said one web (39,40) is disposed
transverse to the plane of said gate (19) and diverts the coolant admitted
via said coolant inlet opening (41) in route to at least one coolant
discharge opening (42, 43).
13. The cement plant of claim 11 wherein at least one of said coolant
discharge openings (42,43) and said coolant inlet opening (41) are located
in an end face of said gate (19).
Description
TECHNICAL FIELD
This invention relates to a device for distributing and/or feeding a hot
flour-like material, in particular a stream of hot cement raw meal, in an
installation for the production of cement clinker from cement raw meal,
which is preheated in a heat-exchanger system and burned to cement clinker
in a cylindrical rotary kiln.
BACKGROUND OF THE INVENTION
In installations for the production of cement clinker from raw meal, which
is preheated and calcined before the burning operation, it is often
necessary to divide a stream of hot cement raw meal into two meal
discharges, that is, to convey hot raw meal into one and/or another meal
discharge. Thus, for example, in the installation for the production of
cement clinker from cement raw meal as shown in European patent document
EP-B 0222 044 published Mar. 8, 1989, the preheated raw meal exiting
downward from the next-to-last (second-lowest) cyclone stage must be
divided in a controlled way into a calcination zone lying in the
clinker-cooler off-gas line (tertiary air line), on the one hand, and a
calcination zone lying in the rotary-kiln off-gas line, on the other. What
is more, in certain dual-train installations (twin installations) where
the cement raw meal of one train, precalcined in the rotary-kiln off-gas
line, undergoes final calcination in the calcination zone of the other
train, operated on hot clinker-cooler off-gas, after the installation has
been started up, precalcined cement raw meal exiting from the lowest
cyclone stage of the rotary-kiln off-gas train must be admitted by means
of a changeover flap not to the rotary kiln but to the secondary
calcination zone of the other train, which is ready for operation.
The distribution or changeover of the stream of hot raw meal has heretofore
been effected with a distributor housing, to the top of which the hot meal
delivery line can be connected and to the bottom of which two hot meal
discharges can be connected, so that the distributor housing is also
called a "breeches pipe" because of its shape. In the breeches pipe, a
flap is pivotably arranged, by means of the pivot actuation of which flap
the stream of hot cement raw meal, which can exhibit a temperature of, for
example, 800 to 900.degree. C., is distributed or changed over. The
pivotable flap in particular is obviously subjected to severe
thermochemical and abrasive wear.
Also subjected to severe wear are "impingement gates," which in cement
plants are built transversely into a hot-gas line coming from the rotary
kiln and/or from the clinker cooler and have the task of uniformly
distributing or suspending, over the hot-gas cross section, preheated
cement raw meal, which is introduced into the hot-gas line from the side.
What is more, in cyclone suspension-type preheater trains having cyclones
arranged one above another through which hot gas flows in order to heat
cement raw meal, "flap boxes" or "oscillating feeders" and also double
oscillating feeders are built into the meal downpipes, in which boxes one
or two weighted oscillating flaps are integrated, which have the task of
holding back the stream of hot gas on the one hand, and on the other hand,
by means of pivoting of the flaps, of allowing the stream of hot raw meal
to pass downward through the meal downpipe after a certain solids burden.
These oscillating flaps are also subjected to severe wear.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to create, especially for cement plant
engineering, a device for distributing and/or feeding a hot stream of
flour-like material, of which device the internal control elements are
subjected to severe wear, in particular the actuator, have a long service
life.
In this invention the device for distributing and/or transporting-feeding a
stream of hot flour-like material, has a pivoting flap/oscillating flap or
impingement gate, which is especially subject to wear, is made as a hollow
plate-shaped body through which coolant flows, by way of at least one
coolant inlet opening and at least one coolant discharge opening. For the
sake of simplicity, outdoor air is used as cooling air, which is forced
through the plate-shaped hollow body by a cooling-air fan or by a
connection to the compressed-air system. The coolant cools the metallic
hollow flap or hollow impingement gate, including the surface thereof.
Solid buildups on the cooled, comparatively lightweight elements according
to the invention are avoided. On the whole, the lifetime or service life
of the hot-meal distributor device or hot-meal feeder is very long.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention and its further features and advantages are explained in more
detail on the basis of exemplary embodiments illustrated schematically in
the Drawing in which:
FIG. 1 shows, in side view, a breeches-pipe-shaped hot-meal distributor
housing having an air-cooled adjustable flap for the
distribution/changeover of a stream of hot meal arriving from above into
one and/or another discharge, viewed in the direction of the arrow I of
FIG. 2;
FIG. 2 shows another side view, offset 90.degree. from FIG. 1, of the
hot-meal changeover box of FIG. 1, having an integrated air-cooled
changeover flap with parts omitted for illustration purposes;
FIG. 3 shows, in vertical section, an air-cooled impingement gate built
into a rotary-kiln off-gas riser below the hot-meal inlet opening;
FIG. 4 shows a somewhat enlarged detail of the vertical section through the
air-cooled impingement gate of FIG. 3;
FIG. 5 is a top view, partly in horizontal section, of the air-cooled
impingement gate of FIG. 4; and
FIG. 6 shows in schematic detail a "dual-train" installation (twin
installation) for the production of cement clinker from cement raw meal,
which has an integrated air-cooled hot-meal changeover flap and an
integrated air-cooled impingement gate.
DETAILED DESCRIPTION OF THE INVENTION
The dual-train installation for the production of cement clinker from
cement raw meal, shown in FIG. 6, has a left train, through which off-gas
from a rotary kiln 10 flows, and a right train, which is supplied with
high-temperature cooler off-gas from hot cooler off-gas via a tertiary air
line 11 of the clinker cooler, not shown. Each of the two trains has
cyclone suspension-type preheater trains operated separately, of each of
which, for the sake of simplicity, only the two lowest cyclone stages 12,
13 and 14, 15 are shown. Of the entire quantity of raw meal processed in
the dual-train installation, approximately 50% of the raw meal, for
example, can be admitted to the left train at 16, and similarly
approximately 50% of the raw-meal quantity, for example, can be admitted
to the right train at 17. The hot raw meal from the second-lowest cyclone
stage 12 of the left train, at roughly 800.degree. C., is introduced into
the hot rotary-kiln off-gas line, at roughly 900 to 1100.degree. C., via
line 18, and there precalcined with or without the addition of fuel. The
point of raw-meal inlet to the rotary-kiln off-gas line is located above
an impingement gate 19, which has the purpose of uniformly distributing
the inlet hot raw meal over the cross section of the rotary-kiln off-gas.
When the installation of FIG. 6 is started up, no hot cooler off-gas from
the clinker cooler is available to operate the right train. At this stage,
the hot meal 20, at roughly 800 to 900.degree. C., separated from the
rotary-kiln off-gas in the lowest cyclone stage 13 of the left train, is
admitted directly to the inlet chamber of the rotary kiln 10 by
apportioning box 21, whose oscillating flap 22 has taken up the right
pivoted position, via the material discharge pipe 23. After startup
operation has come to an end, when sufficiently hot cooler off-gas is
available via the tertiary air line 11, the flap 22 of the changeover box
21 is changed over and the hot meal of the left train is inlet via
hot-meal line 24 to the calciner 26 in the clinker cooler off-gas line 11
of the right train, which is fitted with secondary firing 25, into which
calciner the raw meal from the second-lowest cyclone stage 14 of the right
train is also inlet via line 27. Finally, all the cement raw meal calcined
in the calciner 26 is separated from the hot off-gas stream 28 in the
lowest cyclone 15 of the right train and inlet, as highly (for example,
95%) calcined cement raw meal 29, to the rotary kiln 10, in the sintering
zone of which it is burned to cement clinker.
The hot-meal apportioning box or distributor box 21, having the cooled
control flap 22, is detailed in FIGS. 1 and 2. The flap 22, pivotable
about its bottom end, is made as a hollow body through which coolant
flows, which hollow body is arranged in the breeches-pipe-shaped housing
21 and, depending on the pivoted position, discharges the inlet hot-meal
stream 20 into one and/or the other material discharge 23, 24. As shown in
FIG. 2, at least one web 30, arranged transversely to the flap plane, is
built into the interior of the hollow flap 22, which web diverts the
coolant, cooling air in the exemplary embodiment, admitted via one end of
the hollow flap shaft 31, through the cavity in the flap to the other end
of the hollow flap shaft 31 for the purpose of prolonging the residence
time of the coolant. The cooling air delivered by the cooling-air fan 32
is introduced via a flexible line 33 into one end of the hollow shaft 31,
and the cooling air heated in the flap 22 is discharged to the
surroundings via the other end of the hollow shaft 31 via line 34. The
pivoting flap 22 is actuated via an actuator 35, for example an electrical
actuator having motor 36 and articulated spindle 37, or via hydraulic
pivoting cylinder, pneumatic pivoting cylinder, etc. In any case, the
cooled flap 22 of the hot-meal distributing device according to the
invention, which is subjected to severe thermochemical and abrasive wear,
is distinguished by a long service life.
An oscillating flap of an oscillating feeder or hot-meal downpipe, through
which coolant flows, can be made similarly to the pivoting flap 22 of
FIGS. 1 and 2, through which coolant flows.
The impingement gate 19 of FIG. 6 is detailed in FIGS. 3 to 5. In
distinction to FIG. 6, the impingement gate 19 in FIG. 3 is built into the
rotary-kiln off-gas line or riser 38 from the right side. The hot meal
introduced via the meal line 18 is, on impinging on the impingement gate
19, uniformly distributed by said impingement gate over the entire cross
section of the rotary-kiln off-gas riser. The impingement gate 19 is also
made as a hollow body through which coolant flows, in the interior of
which hollow body there is built-in at least one web arranged transverse
to the gate plane, specifically two webs 39, 40 in the exemplary
embodiment of FIG. 5, which webs divert the coolant, again cooling air in
the exemplary embodiment, admitted via an inlet opening 41 arranged on the
outer end face of the gate, to at least one coolant discharge opening
likewise arranged on the outer end face of the gate, according to FIG. 5
to the discharge openings 42 and 43. The cooling air admitted via opening
41 to the hollow impingement gate 19 can be a high-velocity compressed
air, which by the injector principle draws further quantities of air
located in the vicinity into the hollow body from the surroundings and
conveys said quantities of air through the hollow body for its cooling.
The service life of the air-cooled impingement gate 19 of FIG. 3 is
likewise very long.
The air-cooled impingement gate 19 can be built into not only the
calcination zone of the rotary kiln off-gas line or riser 38 of the cement
clinker production line, as shown in the example of FIG. 6, but also at
another point of the cyclone suspension-type heat-exchanger system, for
example in the off-gas line between the lowest and second-lowest cyclone,
and so forth.
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